1. Field of the Invention
The present invention relates to a system and method for performing minimally invasive cardiac procedures. More particularly, the present invention relates to a robotic system and surgical instruments that may be removably attached thereto, wherein said system aids in performing minimally invasive surgical procedures.
2. Background Information
Blockage of a coronary artery may deprive the heart of the blood and oxygen required to sustain life. The blockage may be removed with medication or by an angioplasty. For severe blockage a coronary artery bypass graft (CABG) is performed to bypass the blocked area of the artery. CABG procedures are typically performed by splitting the sternum and pulling open the chest cavity to provide access to the heart. An incision is made in the artery adjacent to the blocked area. The internal mammary artery (IMA) is then severed and attached to the artery at the point of incision. The IMA bypasses the blocked area of the artery to again provide a full flow of blood to the heart. Splitting the sternum and opening the chest cavity, commonly referred to as xe2x80x98open surgeryxe2x80x99, can create a tremendous trauma on the patient. Additionally, the cracked sternum prolongs the recovery period of the patient.
There have been attempts to perform CABG procedures without opening the chest cavity. Minimally invasive procedures are conducted by inserting surgical instruments and an endoscope through small incision in the skin of the patient. Manipulating such instruments can be awkward, particularly when suturing a graft to an artery. It has been found that a high level of dexterity is required to accurately control the instruments. Additionally, human hands typically have at least a minimal amount of tremor. The tremor further increases the difficulty of performing minimally invasive cardiac procedures.
To perform MIS, the surgeon uses special instruments. These instruments allow the surgeon to maneuver inside the patient. One type of instrument that is used in minimally invasive surgery is forceps, an instrument having a tip specifically configured to grasp objects, such as needles. Because forceps and other instruments designed for minimally invasive surgery are generally long and rigid, they fail to provide a surgeon the dexterity and precision necessary to effectively carry out many procedures in a minimally invasive fashion. For example, conventional MIS forceps are not well suited for manipulating a needle during a minimally invasive procedure, such as during endoscopy. Therefore, many MIS procedures that might be performed, have, as of yet, not been accomplished.
In essence, during open surgeries, the tips of the various instruments may be positioned with six degrees of freedom. However, by inserting an instrument through a small aperture, such as one made in a patient to effectuate a minimally invasive procedure, two degrees of freedom are lost. It is this loss of freedom of movement within the surgical site that has substantially limited the types of MIS procedures that are performed.
Dexterity is lacking in MIS because the instruments that are used fail to provide the additional degrees of freedom that are lost when the instrument is inserted into a patient. One problem associated with this lack of dexterity is the inability to suture when the instruments are in certain positions. As a result, surgeries that require a great deal of suturing within the surgical site are almost impossible to perform because the surgical instruments to enable much of this work are not available.
Another problem associated with MIS is the lack of precision within the surgical site. For procedures such as the MICABG (Minimally Invasive Coronary Artery Bypass Graft), extremely small sutures must be emplaced in various locations proximate the heart. As such, precise motion of the tool at the tip of a surgical instrument is necessary. Currently, with hand positioned instruments, the precision necessary for such suturing is lacking.
As such, what is needed in the art is a tool and class of surgical instruments that may be articulated within the patient such that a surgeon has additional degrees of freedom available to more dexterously and precisely position the tool at the tip of the instrument, as is needed.
Additionally, what is needed in the art is a method and mechanism that provides simple handle, instrument and tool changing capabilities so that various tools may be easily and readily replaced to enable faster procedures to thus minimize operating room costs to the patient and to lessen the amount of time a patient is under anesthesia.
It is to the solution of the aforementioned problems to which the present invention is directed.
U.S. Pat. No. 5,649,956 issued to Jensen et al. and assigned to SRI International discloses a system for holding a surgical instrument. The system includes an instrument holder that can hold a surgical instrument. The instrument can be inserted into a collar assembly an instrument holder. The instrument has a pair of pins that are rotated into circumferential slots of the collar assembly. The collar assembly further contains a latch which secures one of the pins within a corresponding slot to prevent the instrument from being inadvertently detached from the holder. When installed into the collar assembly the surgical instrument can be rotated and actuated through the holder.
The surgical instrument can be detached from the holder by twisting and then pulling the instrument away from the collar. These steps may require valuable time during a surgical procedure. Additionally, it appears that a cover of the holder must be opened to pull the instrument out of the collar. Opening the cover exposes the mechanism that rotates and actuates the instrument. The exposed mechanism may introduce contaminants into the operating site. It would be desirable to provide an instrument and tool driver which allow an operator to quickly change instruments without introducing contaminates into the surgical site.
One embodiment of the present invention is a surgical instrument which has an actuator rod that is coupled to an end effector. The actuator rod is also detachably connected to a push rod that can move relative to a handle to actuate the end effector.